Filling bell for filling a tubeless tire

ABSTRACT

In a filling bell ( 1 ) for filling a tubeless tire ( 30 ) arranged on a wheel rim with a pressurized gas, comprising an annular sealing face ( 3 ) which can be pressed onto a side wall ( 31 ) of the tire and a central opening ( 6 ), into which the wheel rim may penetrate, it is provided for the sealing face ( 3 ) to be formed by an annular flange ( 2 ) which surrounds the opening ( 6 ) and comprises a plurality of wedge-shaped segments ( 4 ), of which the width increases away from the opening ( 6 ) and which are displaceable relative to one another and substantially radially relative to the opening ( 6 ).

CROSS REFERENCE TO RELATED APPLICATION

Applicant claims priority under 35 U.S.C. §119 of German PatentApplication No. 10 2008 020 205.3 filed on Apr. 22, 2008.

FIELD OF THE INVENTION

The invention relates to a filling bell for filling a tubeless tire,arranged on a wheel rim, with a pressurized gas, the filling bellcomprising a sealing face which can be pressed onto a side wall of thetire and which has a central opening into which the wheel rim canpartially penetrate.

BACKGROUND OF THE INVENTION

In automatic series production, motor vehicle wheels which have tubelesstires are usually filled with compressed air by means of an inflationmachine. In so doing, the wheel rim with assembled tire is positioned ona suitable base plate which downwardly seals the wheel during thefilling procedure. Positioned on the upper side of the tire is a fillingbell which upwardly seals the tire and the rim and by which the sidewall of the tire is pressed downwards to such an extent during thefilling procedure that there is produced between the tire bead and wheelrim an annular gap through which the compressed air guided into thefilling bell can flow into the tire. The compressed air which has beenintroduced presses the tire with considerable force against thesupporting plate and the filling bell. Once the filling pressure hasbeen attained, the filling bell is lifted, as a result of which the sidewalls of the tire move apart in an axial direction until the tire beadshave assumed their respective seating positions on the rim. For afilling procedure of this type, the filling bell must have an opening,the diameter of which is large enough so that it does not abut againstthe wheel rim, but can be put over the wheel rim. On the other hand,however, the diameter of the opening must not be so big that the fillingbell radially contacts the upper side wall of the tire outside its highpoint. In that case, the filling bell would obstruct the radial movementof the tire, which could result in the tire bead not springing correctlyinto its seat. If the sealing edge of the bell was located in thevicinity of the cover of the tire, the result might be a high degree ofleakage and inaccuracy in the filling pressure. Thus, a filling bell isonly suitable for a limited size range of motor vehicle wheels.

Thus, for example, only those tires which have a bead seat diameter inthe region of two inch sizes can usually be filled using a filling bellof a specific size.

In order to be able to fill tires of a greater size difference by meansof a tire filling station, it is known, inter alia from EP 1 125 772 B1to use a tire filling bell which has at least two filling rings ofdifferent diameters, the smaller or the larger filling ring being usedaccording to the size of the tire.

DE 198 01 455 A1 discloses a tire inflating device which has threefilling rings and a rim sealing ring which is arranged inside thesmallest filling ring and is expanded to the greater diameter requiredin each case by an adjusting device when one of the two larger fillingrings is used.

SUMMARY OF THE INVENTION

The object of the invention is to provide a tire-filling bell of thespecified type which can be adjusted to different tire sizes and ischaracterized by a large adjustment range.

The filling bell according to the invention comprises a sealing facewhich can be pressed onto a side wall of the tire and which has acentral opening into which the wheel rim can penetrate, the sealing facebeing formed by an annular flange which surrounds the opening andcomprises a plurality of wedge-shaped segments, the width of whichincreases with the distance from the opening and which are displaceablerelative to one another and substantially radially with respect to theopening. In the filling bell according to the invention, the diameter ofthe sealing face can be changed progressively by radially moving anddisplacing the segments with respect to one another and can thus beoptimally adapted in a precise manner to the tire size to be inflated ineach case. The filling bell according to the invention has the furtheradvantage that the sealing face extends by a relatively great amount ina radial direction and thus forms a wide contact surface which reducesthe stress on the tire during the filling procedure. Furthermore, thefilling bell according to the invention provides the possibility ofincreasing the sealing face in a radial direction at the end of thefilling procedure to thereby promote the radial movement of the sidewall of the tire so that the tire bead can spring more easily over thehump into its seat on the rim.

According to a further proposal of the invention, the segments areconnected to one another at their divergent edges in a positive andlongitudinally displaceable manner. Such a connection of the segmentsproduces a closed, annular unit which prevents an uncontrolledindividual movement of the separate segments. All the segments can onlybe moved together in the same direction, either radially outwards orradially inwards, the extent of the movement being the same for all theelements. The segments always remain in engagement with one another andthe opening which they surround always retains its central position.

To be able to effectively seal the filling bell outwards, it is furtherprovided that a sealing element is positioned between each of thedivergent edges of adjacent segments. The sealing element is preferablya profiled strip made of plastics material which fills the space betweenthe segments and forms a sliding guide for moving the segments. Thesegments can also have holes for supplying a lubricant in the region ofthe sliding guide. In this manner, frictional resistances can be reducedwhich counteract the adjustment of the segments.

According to a further proposal of the invention, the segments can have,on their side remote from the sealing face, a journal by which they areradially displaceably and rotatably guided and held on a carrier plate.Furthermore, an actuation element can be provided which can collectivelymove the segments. A simple and advantageous embodiment of the actuationelement consists of a disc cam which is rotatably mounted on the fillingbell and has effective surfaces which act on the journals of thesegments and extend in a radial and circumferential direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail in the following withreference to embodiments which are shown in the drawings, in which:

FIG. 1 is a view of the sealing face of a filling bell according to theinvention in an adjustment having the smallest diameter,

FIG. 2 is a view of the sealing face of a filling bell according to theinvention in an adjustment having the greatest diameter,

FIG. 3 is a perspective view of a first embodiment of a filling bellaccording to the invention,

FIG. 4 is a cross-sectional view through a junction between two segmentsof a filling bell according to the invention,

FIG. 5 is a partial view of the filling bell according to FIG. 3 restingagainst a tire and adjusted to a smaller diameter,

FIG. 6 is a partial view of the filling bell according to FIG. 3 restingagainst a tire and adjusted to the largest possible diameter,

FIG. 7 is a partial view of another embodiment of a filling bellaccording to the invention,

FIG. 8 shows an enlarged detail of the view according to FIG. 7, and

FIG. 9 is a schematic representation to illustrate the tire movement atthe end of a tire inflation procedure.

DETAILED DESCRIPTION OF THE DRAWINGS

The filling bell 1 shown in FIGS. 1 to 3 has a planar, annular sealingface 3 formed by an annular flange 2. The annular flange 2 consists oftwelve congruent, wedge-shaped segments 4 which have a wedge angle of30°. The segments 4 have inwardly directed acute ends 5 and a circulararc-shaped outer edge 7. Strung together and arranged in the samedirection, the twelve segments 4 form a closed ring which extends overan angle of 360°. The segments 4 are arranged such that they each restclosely against one another with their divergent edges.

The diameter of the annular flange 2 formed by the segments 4 depends onthe relative position assumed by the individual segments 4 with respectto one another. In the arrangement shown in FIG. 1, the acute, inwardlydirected ends 5 of the segments 4 are arranged very closely together.Accordingly, there remains free in the center of the annular flange 2only a relatively small opening 6. Seen purely geometrically, thesegments 4 can also be moved to such an extent towards the center thattheir acute ends 5 meet at a point, thereby producing a closed circularsurface. However, this would be of little use when providing a fillingbell for filling tires, as an opening for the penetration of the wheelrim must be provided in the center of the filling bell.

If, as shown in FIG. 2, the segments 4 are moved with respect to oneanother such that their acute ends 5 are at a greater distance from oneanother, then as a result the diameter of the opening 6 and accordinglyalso the diameter of the annular flange 2 is increased.

In the two positions of the segments 4 shown in FIGS. 1 and 2, the outercontour of the annular flange 2 is irregular. This is due to the factthat the outer edge 7 of the segments 4 corresponds to an externaldiameter of the annular flange 2 which is greater than the externaldiameter in FIG. 1 and smaller than the external diameter in FIG. 2. Theselection of an average diameter for determining the outer contour ofthe segments 4 has the advantage that the resulting deviations in theouter contour from the circular shape do not become too great whenfalling below the average diameter and also when exceeding said averagediameter and a sufficiently large, closed annular surface remainsavailable.

It can be seen from FIG. 3 how the annular flange 2 formed from segments4 is positioned on and secured to the filling bell 1. The filling bell 1has a cylindrical bell ring 10, the internal diameter of whichdetermines the maximum size of the bell opening. Secured to the upperedge 11 of the bell ring 10 is a cover plate (not shown here) whichtightly upwardly seals the bell ring 10 and on which are fitted thenecessary connections for filling and emptying the interior of the bell.The cover plate is also attached to a lifting device by which thefilling bell 1 can be moved in the direction of the cylinder axis of thebell ring 10. Attached to the lower edge of the bell ring 10 is anannular carrier plate 12 which extends radially outwards from the edgeof the bell ring 10. For reinforcement purposes, the carrier plate 12 isalso connected on its upper side to the outside of the bell ring 10 byradial webs 13, as can be seen particularly clearly in FIGS. 5 and 6.The carrier plate 12 has in regular spacings a number of radial slots 14corresponding to the number of the segments 4, which radial slots 14 areopen radially outwards.

Positioned on the lower side of the carrier plate 12 are the segments 4which together form the annular flange 2. In this respect, the segments4 are held and guided on the carrier plate 12 by journals 15. Eachsegment 4 carries a journal 15 which penetrates a radial slot 14 in thecarrier plate 12 with a cylindrical shaft 16. On its free end, the shaft16 bears a head 17 of a relatively large diameter which rests on theupper side of the carrier plate 12 and thereby firmly holds the segment4, connected to the journal 15, on the carrier plate 12. The journals 15can be moved in a radial direction along the radial slots 14 to enablethe diameter of the annular flange 2 to be changed.

As can be seen in particular from FIG. 4, the segments 4 are connectedtogether at their adjacent edges in a positive and longitudinallydisplaceable manner. FIG. 4 shows a cross section through a junctionbetween the right-hand edge of a first segment 4 a and the left-handedge of a second segment 4 b. The right-hand edge of segment 4 a has onthe upper side remote from the sealing face 3 a longitudinal groove 20and a rib 21 which delimits the longitudinal groove 20 on the outside.Longitudinal groove 20 and rib 21 are rectangular in cross section, andthe width of the longitudinal groove 20 is approximately double thewidth of the rib 21. The height of the rib 21 is approximately twothirds the thickness of segment 4 a. The left-hand edge of segment 4 bis configured mirror-inversely to the right-hand edge of segment 4 a andaccordingly has on the side of the sealing face 3 a longitudinal groove22 and a rib 23. Both segments are arranged with respect to one anothersuch that their ribs 21, 23 engage in each case in the longitudinalgrooves 20 and 22, respectively. There remains between the periphery ofthe ribs 21, 23 and the periphery of the longitudinal grooves 20, 22 anS-shaped gap of an approximately constant width which is filled with asealing element 25 in the form of a profiled strip. The sealing element25 seals the junction both in the longitudinal direction of the groovesand ribs and in the transverse direction. The sealing element 25 issecured to segment 4 b by, for example, adhesion. The sealing element 25can slide on segment 4 a. This allows a relative movement between thesegments 4 a, 4 b in the direction of the longitudinal grooves 20, 22.To reduce the frictional resistance between the sealing element 25 andsegment 4 a, segment 4 a has holes 26 for supplying a lubricant into theslide gap.

The described connection consisting of longitudinal grooves, ribs andsealing element is provided at all adjacent edges of the segments 4, sothat all segments 4 are connected together to form an annular unit.Within this unit, the individual segments 4 can only change theirposition together, in the same direction and by the same amount. Thus,the diameter of the annular flange 2 formed by the segments 4 can bechanged by moving the segments 4, the annular flange 2 still retainingits closed annular shape and only the contour of the inner or outer edgechanging. Furthermore, the mounting of the annular flange 2 in theradial slots 14 in the carrier plate 12 by means of the journals 15arranged on the segments 4 ensures that the annular flange 2 retains itsconcentric position with respect to the bell ring 10 in all sizepositions.

FIG. 5 shows an adjustment in which the opening 6 in the annular flange2 is significantly smaller than the internal diameter of the bell ring10. This adjustment is intended for filling a relatively small tire 30which is shown here without the associated wheel rim. In this case, theannular flange 2 rests with its sealing face 3 on the side wall 31 ofthe tire 30 and thereby outwardly seals the interior of the filling bell1 on the tire 30. The compressive force which acts on the annular flange2 during the filling procedure is directly transmitted onto the carrierplate 12 by the annular flange 2, tilting forces which arise on thesegments 4 being absorbed by the journals 15.

FIG. 6 shows the use of the filling bell 1 on a tire 32 of a relativelylarge diameter. In this case, the annular flange 2 is adjusted such thatits opening 6 has the greatest possible internal diameter which isapproximately the same as the internal diameter of the bell ring 10. Inthis position, the segments 4 of the annular flange 2 rest with theirrear side completely on the carrier plate 12, such that the compressiveforces arising during the filling procedure can be supported in atrouble-free manner.

FIGS. 7 and 8 show a further embodiment of a filling bell 41 which,unlike the filling bell 1, comprises a device for synchronouslyadjusting the annular flange 2 and the segments 4. For this purpose, theupper side of the carrier plate 12 is planar and is not interrupted bywebs 13. Arranged on the carrier plate 12 is a disc cam 42 which hasregularly-spaced openings 43 which are each in the shape of an elongatedhole with parallel longitudinal sides and semi-circular end portions.The openings 43 are arranged in a rotationally symmetrical manner andobliquely such that their parallel side walls 44 form approximately atan angle of 45° to a radial line which crosses them. Engaging in eachopening 43 is a head 17 of a journal 15 by which a segment 4 is held onthe carrier plate 12. The width of the openings 43 is slightly greaterthan the diameter of the heads 17, such that the heads 17 can easilymove in a longitudinal direction in the openings 43. The disc cam 42surrounds the bell ring 10 and is mounted rotatably thereon.

In the position of the disc cam 42 shown in FIGS. 7 and 8, the segments4 have moved radially inwards to a considerable extent such that theyproject inwards over the bell ring 10 and form an opening 6 which isconsiderably smaller than the internal diameter of the bell ring 10. Toadjust the segments 4 in the sense of enlarging the opening 6, itsuffices to rotate the disc cam 42 in the drawing in an anti-clockwisedirection with respect to the carrier plate 12. Due to a rotation ofthis type, the heads 17 of the individual segments 4 are pressedradially outwards by the side walls 44 of the openings 43 and thesegments 4 are moved accordingly, the segments 4 also sliding relativeto one another on their positively connected edges and performing aslight rotation about their journal axis with respect to the carrierplate 12. Regardless of the various instantaneous movements, thereresults, however, an increase in the annular flange 2 and thus also inthe opening 6, which does not change its concentric position withrespect to the bell ring 10. The greatest possible diameter of theopening 6 is attained when the heads 17 of the journals 15 have enteredthe radially outer end position in the openings 43 in the disc cam 42.

The disc cam 42 can either be rotated manually using a suitable lever orin automatically operating installations by means of a suitable motordrive.

It can be seen from FIG. 8 how the segments 4 can be sealed with respectto the carrier plate 12. For this purpose, the carrier plate 12 has onits lower side an annular groove 46 in which is positioned a sealingring 47, in particular an O ring which rests on the segments 4. Thismeasure ensures that when tires are being filled, the compressed air orcompressed gas cannot escape outwards between the carrier plate 12 andthe segments 4.

In addition to the progressive adaptation of the diameter of the sealingface of the tire filling bell to tire or rim diameters which vary insize, the filling bell embodiment according to the invention alsoaffords the possibility of promoting the movement of the tire at the endof the filling procedure such that the tire achieves the predeterminedassembly end position on the rim with greater accuracy and reliability.FIG. 9 illustrates the situation towards the end of the tire fillingprocedure. The tire 50 has been filled with compressed air and ispressed with its upper side wall 51 against the annular flange 2, formedfrom segments 4, of the filling bell 1. In the opposite direction, thelower side wall of the tire 50 and the rim 52 rest on a supporting plate(not shown). In order for the tire 50 to be able to spring with its bead53 over the hump 54 into its seat 55 on the rim flange 56 under theeffect of the filling pressure, the side wall 51 must be able to moveradially outwards. In the filling stations and filling bells knownhitherto, the tire must overcome the frictional forces on the edge ofthe filling bell and the supporting plate. If the friction is too great,this can mean that the tire bead 53 does not spring over the hump anddoes not fit snugly against the rim flange 56 in the concave surface ofthe seat 55. If this is the case, the wheel will exhibit a high degreeof non-uniformity when it rolls.

Assembly faults of this type can be effectively avoided by the fillingbell according to the invention. Thus, it can be possible during thecritical moment of the filling procedure to actuate the annular flange2, for example using the disc cam 42, such that it increases itsdiameter. Such a radial increase in the annular flange 2 promotes theradial movement of the side wall of the tire and makes it easier tospring over the hump. Furthermore, an alternative could be to switch thedrive for radially adjusting the annular flange 2 to be moment-free andconsequently to allow the tire 50 to automatically expand the annularflange 2. However, since the segments of the annular flange 2 not onlymove radially but at the same time require a tangential displacement, itmight be expedient in this case to additionally mount the filling bellsuch that it is freely rotatable to facilitate the movement of thesegments.

Since comparable problems also occur in the case of the lower side wallof the tire, it can be advantageous when a radially adjustable annularflange consisting of wedge-shaped segments is also positioned in theregion of the supporting plate, which annular flange can follow thedeformation of the side wall of the tire by means of a drive orautomatically.

1. Filling bell for filling a tubeless tire arranged on a wheel rim witha pressurized gas, comprising an annular sealing face which can bepressed onto a side wall of the tire and a central opening, into whichthe wheel rim can penetrate, wherein the sealing face is formed by anannular flange which surrounds the opening and comprises a plurality ofwedge-shaped segments having divergent edges, the width of said segmentsincreasing away from the central opening, and said segments beingdisplaceable relative to one another and substantially radially relativeto the opening.
 2. Filling bell according to claim 1, wherein thesegments are positively and longitudinally displaceably connected to oneanother at their divergent edges.
 3. Filling bell according to claim 1,wherein a sealing element is arranged between each of the divergentedges of adjacent segments.
 4. Filling bell according to claim 3,wherein the sealing element is a profiled strip made of a plasticsmaterial which fills the space between the segments and forms a slidingguide for moving the segments.
 5. Filling bell according to claim 1,wherein the segments comprise holes for supplying a lubricant. 6.Filling bell according to claim 1, wherein on their side remote from thesealing face the segments have a journal, by which means they areradially displaceably and rotatably guided and held on a carrier plate.7. Filling bell according to claim 1 wherein the segments arecollectively displaceable by an actuation element.
 8. Filling bellaccording to claim 7, wherein the actuation element is a disc cam whichis rotatably mounted on the filling bell and has effective surfaceswhich act on the journal and extend radially and in the circumferentialdirection.
 9. Filling bell according to claim 7, wherein a journal has acylindrical shaft and at its free end a cylindrical head with a largerdiameter, and wherein the shaft of the journal penetrates through aradial slot in the carrier plate and the head lies on the rear side ofthe carrier plate remote from the segment and engages in a drivingrecess of the actuation element.